CN108980359B

CN108980359B - Magnetic fluid sealing structure

Info

Publication number: CN108980359B
Application number: CN201810914080.XA
Authority: CN
Inventors: 杨小龙; 陈帆; 高名乾
Original assignee: Guangxi University of Science and Technology
Current assignee: Guangxi University of Science and Technology
Priority date: 2018-08-13
Filing date: 2018-08-13
Publication date: 2020-05-05
Anticipated expiration: 2038-08-13
Also published as: CN108980359A

Abstract

The invention discloses a novel magnetic fluid sealing structure, which comprises a hollow shell, wherein a plurality of pole shoes are arranged in a space between the outer surface of a shaft and the inner wall of the shell at intervals along the axial direction, the pole shoes are annular, the outer circular surfaces of the pole shoes are abutted against the inner wall of the shell, pole teeth are arranged on the inner circular surfaces of the pole shoes, a permanent magnet is clamped between every two adjacent pole shoes, a gap exists between each pole tooth and the outer surface of the shaft, magnetic fluid is injected into the gap, the width of each pole shoe is sequentially increased from the high-pressure side to the low-pressure side, and the number of; the permanent magnets are axial magnetizing permanent magnet rings, and the polarities of the magnetic poles of the adjacent permanent magnets are opposite. The sealing capability of the magnetic fluid under the pole shoe on the high-pressure side is smaller than that of the magnetic fluid under the pole shoe on the low-pressure side, and the pressure resistance of the pole shoe is gradually increased from the high-pressure side to the low-pressure side, so that the magnetic fluid sealing under all the pole shoes can play a role, and the sealing pressure resistance is ensured.

Description

Magnetic fluid sealing structure

Technical Field

The invention belongs to the sealing technology of mechanical engineering, and particularly relates to a magnetic fluid sealing structure.

Background

The existing magnetic fluid sealing structure for the reciprocating motion of a shaft generally comprises a shell with a hollow cavity and the shaft, wherein a permanent magnet and a pole shoe are arranged between the shaft and the shell for magnetic fluid sealing, and the inner ring of the pole shoe is provided with pole teeth.

One of the methods for improving the pressure resistance of the magnetic fluid seal is to increase the number of magnetic sources in the magnetic circuit of the magnetic fluid seal and improve the shape of the pole piece, such as the sealing devices described in the patents with publication numbers CN204805552U and CN 202418592U. Although the two sealing devices described in the above documents have greatly improved sealing performance with respect to common magnetic fluids, the prior art still has the following drawbacks:

in the multi-stage sealing structure in the prior art, the number of pole teeth on each pole shoe is the same. The inventor finds out through experiments that if the pressure resistance of the magnetic fluid seal of the high-pressure side pole shoe in two adjacent pole shoes is larger than that of the magnetic fluid seal of the adjacent low-pressure side pole shoe from the high-pressure side to the low-pressure side, the magnetic fluid seal of the low-pressure side does not work, namely the seal of the low-pressure side is similar to a dummy. For the multi-stage sealing structure, since the magnetic fluid seal on the low-pressure side cannot play a role, the arrangement of the pole shoes in multiple stages only increases the volume of the magnetic fluid sealing structure, and wastes more cost.

Disclosure of Invention

In view of the above problems, the present invention aims to provide a magnetic fluid sealing structure that enables all pole shoes to function.

The technical scheme for solving the problems is as follows: a magnetic fluid sealing structure comprises a hollow shell, wherein one end of the shell is closed, the other end of the shell is open, a through hole is formed in the center of the closed end face of the shell, the magnetic fluid sealing structure further comprises a shaft penetrating through the through hole to the inner cavity of the shell, a plurality of pole shoes are arranged in a space between the outer surface of the shaft and the inner wall of the shell at intervals along the axial direction, the pole shoes are annular, the outer circular surfaces of the pole shoes are abutted against the inner wall of the shell, pole teeth are arranged on the inner circular surfaces of the pole shoes, a permanent magnet is clamped between every two adjacent pole shoes, a gap exists between each pole tooth and the outer surface of the shaft, magnetic fluid is injected into the gap, the width;

the permanent magnets are axial magnetizing permanent magnet rings, and the polarities of the magnetic poles of the adjacent permanent magnets are opposite.

The scheme changes the existing structure, changes the width of the pole shoe, and changes the corresponding tooth number. Through the structural change, the sealing capability of the magnetic fluid under the pole shoe at the high-pressure side is artificially manufactured to be smaller than that of the magnetic fluid under the pole shoe at the low-pressure side, so that the defect condition in the background technology can be avoided. From the high-pressure side to the low-pressure side, the pressure resistance of the pole shoes is gradually increased, so that the magnetic fluid seal under all the pole shoes can play a role, and the sealing pressure resistance is ensured.

Preferably, the number of teeth on adjacent pole pieces differs by 1 or 2.

Preferably, the number of the pole teeth on each pole shoe is 1-15.

Furthermore, a magnetism isolating ring is arranged between the pole shoe closest to the closed end of the shell and the inner wall of the closed end of the shell.

Further, the pole shoe closest to the open end of the shell is tightly sealed in the inner cavity of the shell through an end cover.

Preferably, the number of the permanent magnets is 2-10.

Preferably, the number of the pole shoes is 3-10.

Preferably, the size of the gap between the pole teeth and the outer surface of the shaft is 0.05-3 mm.

According to the invention, through the structural change, the sealing capability of the magnetic fluid under the pole shoe on the high-pressure side is artificially manufactured to be smaller than that of the magnetic fluid under the pole shoe on the low-pressure side, and the pressure resistance capability of the pole shoe is gradually increased from the high-pressure side to the low-pressure side, so that the magnetic fluid sealing under all the pole shoes can play a role, and the sealing pressure resistance performance is ensured.

Drawings

The invention will be further explained with reference to the drawings.

FIG. 1 is a schematic view of a magnetic fluid sealing structure according to the present invention.

In the figure: 1-shaft, 2-shell, 3-pole shoe, 4-end cover, 5-magnetism isolating ring, 6-pole tooth and 7-permanent magnet.

Detailed Description

As shown in fig. 1, the magnetic fluid sealing structure comprises a hollow shell 2, wherein one end of the shell 2 is closed, and the other end of the shell 2 is open. A through hole is arranged in the center of the closed end surface of the shell 2.

And the shaft 1 is arranged in the inner cavity of the shell 2 from the through hole in a penetrating way. A plurality of pole shoes 3 are axially spaced in the space between the outer surface of the shaft 1 and the inner wall of the housing 2.

The pole shoe 3 is annular, and the outer circular surface of the pole shoe 3 is abutted to the inner wall of the shell 2. Pole teeth 6 are arranged on the inner circular surface of the pole shoe 3. And a permanent magnet 7 is clamped between two adjacent pole shoes 3. A gap exists between the pole teeth 6 and the outer surface of the shaft 1, and magnetic fluid is injected into the gap.

The width of the pole shoe 3 is increased in sequence from the high-pressure side to the low-pressure side, and the number of the pole teeth 6 on the pole shoe 3 is increased in sequence.

The permanent magnet 7 is an axial magnetizing permanent magnet ring. The polarities of the poles of adjacent permanent magnets are opposite.

The number of pole teeth 6 on adjacent pole shoes 3 differs by 1 or 2.

The number of the pole teeth 6 on each pole shoe 3 is 1-15.

The number of the permanent magnets 7 is 2-10.

The number of the pole shoes 3 is 3-10.

The size of the gap between the pole teeth 6 and the outer surface of the shaft 1 is 0.05-3 mm.

A magnetism isolating ring 5 is arranged between the pole shoe 3 closest to the closed end of the shell 2 and the inner wall of the closed end of the shell 2. The pole shoe 3 closest to the open end of the housing 2 is pressure-sealed to the interior of the housing 2 by means of an end cap 4.

Claims

1. The utility model provides a magnetic current body seal structure, includes hollow casing (2), casing (2) one end is sealed, the other end is opened, and it has the through-hole to open at the closed end face center of casing (2), still includes axle (1) of wearing to establish to casing (2) inner chamber from the through-hole, is equipped with a plurality of pole shoes (3) along axial interval in the space between axle (1) surface and casing (2) inner wall, pole shoe (3) are cyclic annular, and pole shoe (3) excircle face and casing (2) inner wall butt are equipped with utmost point tooth (6) on the pole shoe (3) inner circle face, press from both sides between two adjacent pole shoes (3) and are equipped with permanent magnet (7), have the clearance between utmost point tooth (6) and axle (1) surface, and clearance department notes have magnetic current body, its characterized in that: the width of the pole shoe (3) is sequentially increased in the direction from the high-pressure side to the low-pressure side, and the number of the pole teeth (6) on the pole shoe (3) is sequentially increased;

the permanent magnet (7) is an axial magnetizing permanent magnet ring, and the polarities of the magnetic poles of the adjacent permanent magnets are opposite.

2. The magnetic fluid sealing structure according to claim 1, wherein: the number of the pole teeth (6) on the adjacent pole shoes (3) is different by 1 or 2.

3. A magnetic fluid sealing structure according to claim 1 or 2 wherein: the number of the pole teeth (6) on each pole shoe (3) is 1-15.

4. The magnetic fluid sealing structure according to claim 1, wherein: a magnetism isolating ring (5) is arranged between the pole shoe (3) closest to the closed end of the shell (2) and the inner wall of the closed end of the shell (2).

5. The magnetic fluid sealing structure according to claim 1, wherein: the pole shoe (3) closest to the open end of the shell (2) is pressed and sealed in the inner cavity of the shell (2) through an end cover (4).

6. The magnetic fluid sealing structure according to claim 1, wherein: the number of the permanent magnets (7) is 2-10.

7. The magnetic fluid sealing structure according to claim 1, wherein: the number of the pole shoes (3) is 3-10.

8. The magnetic fluid sealing structure according to claim 1, wherein: the gap between the pole teeth (6) and the outer surface of the shaft (1) is 0.05-3 mm.